It was asked Is trash talking legal in WSOP?, but my question is different from that post.
There was a hand played between William Kassouf and Stacy Matuson that caused a big controversy at WSOP 2016. It is the first hand in this video.
This video does not show what happened before the river card, however after the river card, Kassouf is table talking normally without anything seeming rude and did not speak directly to what he had or she might have.
After that, supervisor warned him about talking. Kassouf continued normal conversation to Matuson, in my opinion he was not saying anything in violation of the rules.
With tournament Director Jack Effel still at the table Kassouf attempted some sign language apparently trying to say to Matuson "If you show I will Show". At this point in the video Norman Chad speaks up saying:
Now he is talking without words.
After the hand, Jack give Kassouf a one round penalty, saying:
If you stay at your seat and don't leave the table, you will receive a two round penalty.
I find this situation really weird. Talking is a part of poker. It might tilt you, or not.
Is "talking" that influences action illegal? Is there any written rule about it? How did this example "influence" the action?